Abstract:
We present a novel framework for automatically simplifying the dynamics
computation of particle systems to improve simulation speeds. Our approach
is based on physically-based subdivision scheme to generate a hierarchy
of approximated motion models or simulation levels of detail (SLOD). At
each time step, the SLODs are updated on the fly and the appropriate SLOD
is adaptively chosen to reduce the computational costs. We have developed
a prototype implementation and tested it on the simulation of a water fountain
and a galaxy system. The preliminary results show a significant performance
gain on these scenarios with little or no loss on the visual appearance
of the simulation, indicating the potential to generalize this approach
to other dynamical systems.

FountainThis
compares a fountain simulation without SLODs to one with SLODs. The image
on the right uses SLODs and is able to maintain a rate of 30 fps while
the left image noticably slows down as the number of particles increases.

Changing
Region of InterestThis
shows one stream from the above fountain rendered as simple colored dots
to help distinguish the individual clusters. The coarser Region of Interest
of interest is moved and resized as the simulation runs. Clusters
automatically break up and regroup accordingly. The wire cube shows
the region of coarser detail.

Close-up
of SLOD ChangeThis
shows two particle streams colliding with two cones. The left stream
and cone are all just one coarse area of simulation. This leads to
unnatural looking bounces off of the left cones. The right cone is
in a finer Region of Interest. The large clusters are broken into
smaller clusters just before bouncing off the right cone giving a more
natural reaction. Some particles are then regrouped as the move below
the right cone.

GalaxyThis
shows the SLOD algorithm working on a much more computationally intensive
n-body simulation. This is a simulated star field of approximately
10,000 stars. Here the speed up due to SLOD is much greater.
This video starts at a very high level of detail and gradually relaxes
the constraints to increase the frame rate.

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